Hey Martin,
Welcome to BP first off. It is a great place to really network and find folks you need for your team - professionals and jv partners - I want to address the last bit as I work for a loan brokering company. There are all sorts of folks that do lending in the private space from institutions to individuals, the more experienced they are they are going to ask the hard questions about the deals you are bringing to them. Like your experience, experience of anyone else you have in the deal and timeline for their expected return. They are going to ask for a plan and bpo's, contract (if available), liquidity or cash you are bringing to the deal, anything you might haave to put up for collateral and a few other things depending on the lender. So when bringing a deal to anyone coming off prepared will get the ball rolling faster. Rates and terms are going to vary with the institutions as well.
Joint venture or partnerships is the terms come to mind with your second point. And it should depend in what kind of equity and experience they bring to the deal and how the operating agreements are written up as to what to pay out to them. I would say consult a legal person to help you with this but it always seems to me that if it is a rental you split the monthly profit. Some folks might even be open to quarterly payouts. Keep it simple. If it is flip they would see their return at the close of the flip. Hire a bookkeeper/accountant (if you haven't already) to keep it in order. And you would have had put into the budget money to be set aside for maintenance and other expenses that would be expected by any partner you bring on.
I hope that my answer has given you some things to consider and left enough for other to jump in with their thoughts and experience.
I would be open to being that resource in the private lending space for you reach out and lets connect offline!